Computer Science Chapter 3 Exercise
False
A key frame is used in temporal compression to represent the changes from one frame or another.
64
How many things can be represented with six bits?
False
In the ASCII character set, no distinction is made between the uppercase and lowercase letters.
True
Keyword encoding places frequently used words with a single character set.
Signed-magnitude representation
The representation for numbers you have used since grade school is called ________.
True
Vector graphics represent images in terms of lines and geometric shapes.
Analog
________ data is a continuous representation of information.
Digital
________ data is a discrete representation of information.
True
A CD stores audio information in a binary format.
False
A computer must be use the binary number system to represent information.
False
A computer represents information in an analog form.
True
A digital signal represents one of two values at any point in time.
True
An RGB value represents a color using three numeric values.
Sampling
An audio signal is digitized by ________ its value at regular intervals.
True
An audio signal is digitized by sampling it at regular intervals.
True
Bitmap, Gif, and JPEG are all examples of raster graphic formats.
True
Four bits can be used to represent one of two values at any point in time.
32
How many things can be represented with five bits?
16
How many things can be represented with four bits?
128
How many things can be represented with seven bits?
Frequency of use
Huffman codes are created based on the ________ of the character.
True
Huffman encoding uses variable-length binary strings to represent characters.
Radix
If the number base is other than base 10, we call the decimal point the ________.
False
Indexed color increases the number of colors that must be used in an image, and thus increases the file size.
A sweeping second hand is an analog device. The motion of the hand is continuous.
Is a clock with a sweeping second hand an analog or a digital device?
True
Lossless compression means the data can be retrieved without losing any of the original information.
True
Overflow occurs when the value that we compute cannot be fit into the number of bits we have allocated for the result.
False
Run-Length encoding is very good at compressing English text.
True
The MP3 audio format discards information that can not be heard by humans.
True
The Unicode character set includes all of the characters in the ASCII character set.
True
The sign-magnitude representation of numbers has two representations for zero.
Digitizing is the act of breaking continuous information into discrete pieces so that we can represent each piece separately.
What does it mean to digitize something?
Pulse Code Modulation is a signal that jumps sharply between two extremes.
What is pulse code modulation?
A lossless data compression is a technique in which no information is lost. A lossy data compression is a technique in which some information may be lost.
What is the difference between lossless and lossy data compression?
Computers are discrete, finite machines. Analog information is continuous and infinite. Thus, computers cannot represent analog information directly; the analog information must be converted into a digital form.
Why do computers have difficulty with analog information?
Data compression refers to reducing the amount of space needed to store a piece of data. Although computer storage is relatively cheap, as the amount of data keep increasing rapidly the cost of storage is a factor. However, the most important reason for compressing data is that more and more we share data. The Web and its underlying networks have limitations on bandwidth that define the maximum number of bits or bytes that can be transmitted from one place to another in a fixed amount of time.
Why is data compression an important topic today?